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authorJohan Almbladh <johan.almbladh@anyfinetworks.com>2021-09-14 11:18:41 +0200
committerDaniel Borkmann <daniel@iogearbox.net>2021-09-28 09:26:29 +0200
commit18935a72eb25525b655262579e1652362a3b29bb (patch)
tree9e38f0d1d556c0f493d301ef01c564f393f61d3a /lib
parentf536a7c80675e4875e50df9182881d7678e27651 (diff)
bpf/tests: Fix error in tail call limit tests
This patch fixes an error in the tail call limit test that caused the test to fail on for x86-64 JIT. Previously, the register R0 was used to report the total number of tail calls made. However, after a tail call fall-through, the value of the R0 register is undefined. Now, all tail call error path tests instead use context state to store the count. Fixes: 874be05f525e ("bpf, tests: Add tail call test suite") Reported-by: Paul Chaignon <paul@cilium.io> Reported-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn> Link: https://lore.kernel.org/bpf/20210914091842.4186267-14-johan.almbladh@anyfinetworks.com
Diffstat (limited to 'lib')
-rw-r--r--lib/test_bpf.c37
1 files changed, 27 insertions, 10 deletions
diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 7f8ad4fa4add..a94ab634f947 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -12180,10 +12180,15 @@ static __init int test_bpf(void)
struct tail_call_test {
const char *descr;
struct bpf_insn insns[MAX_INSNS];
+ int flags;
int result;
int stack_depth;
};
+/* Flags that can be passed to tail call test cases */
+#define FLAG_NEED_STATE BIT(0)
+#define FLAG_RESULT_IN_STATE BIT(1)
+
/*
* Magic marker used in test snippets for tail calls below.
* BPF_LD/MOV to R2 and R2 with this immediate value is replaced
@@ -12253,32 +12258,38 @@ static struct tail_call_test tail_call_tests[] = {
{
"Tail call error path, max count reached",
.insns = {
- BPF_ALU64_IMM(BPF_ADD, R1, 1),
- BPF_ALU64_REG(BPF_MOV, R0, R1),
+ BPF_LDX_MEM(BPF_W, R2, R1, 0),
+ BPF_ALU64_IMM(BPF_ADD, R2, 1),
+ BPF_STX_MEM(BPF_W, R1, R2, 0),
TAIL_CALL(0),
BPF_EXIT_INSN(),
},
- .result = MAX_TAIL_CALL_CNT + 1,
+ .flags = FLAG_NEED_STATE | FLAG_RESULT_IN_STATE,
+ .result = (MAX_TAIL_CALL_CNT + 1 + 1) * MAX_TESTRUNS,
},
{
"Tail call error path, NULL target",
.insns = {
- BPF_ALU64_IMM(BPF_MOV, R0, -1),
+ BPF_LDX_MEM(BPF_W, R2, R1, 0),
+ BPF_ALU64_IMM(BPF_ADD, R2, 1),
+ BPF_STX_MEM(BPF_W, R1, R2, 0),
TAIL_CALL(TAIL_CALL_NULL),
- BPF_ALU64_IMM(BPF_MOV, R0, 1),
BPF_EXIT_INSN(),
},
- .result = 1,
+ .flags = FLAG_NEED_STATE | FLAG_RESULT_IN_STATE,
+ .result = MAX_TESTRUNS,
},
{
"Tail call error path, index out of range",
.insns = {
- BPF_ALU64_IMM(BPF_MOV, R0, -1),
+ BPF_LDX_MEM(BPF_W, R2, R1, 0),
+ BPF_ALU64_IMM(BPF_ADD, R2, 1),
+ BPF_STX_MEM(BPF_W, R1, R2, 0),
TAIL_CALL(TAIL_CALL_INVALID),
- BPF_ALU64_IMM(BPF_MOV, R0, 1),
BPF_EXIT_INSN(),
},
- .result = 1,
+ .flags = FLAG_NEED_STATE | FLAG_RESULT_IN_STATE,
+ .result = MAX_TESTRUNS,
},
};
@@ -12384,6 +12395,8 @@ static __init int test_tail_calls(struct bpf_array *progs)
for (i = 0; i < ARRAY_SIZE(tail_call_tests); i++) {
struct tail_call_test *test = &tail_call_tests[i];
struct bpf_prog *fp = progs->ptrs[i];
+ int *data = NULL;
+ int state = 0;
u64 duration;
int ret;
@@ -12400,7 +12413,11 @@ static __init int test_tail_calls(struct bpf_array *progs)
if (fp->jited)
jit_cnt++;
- ret = __run_one(fp, NULL, MAX_TESTRUNS, &duration);
+ if (test->flags & FLAG_NEED_STATE)
+ data = &state;
+ ret = __run_one(fp, data, MAX_TESTRUNS, &duration);
+ if (test->flags & FLAG_RESULT_IN_STATE)
+ ret = state;
if (ret == test->result) {
pr_cont("%lld PASS", duration);
pass_cnt++;